METHODS AND MEANS OF DIVERSE SYNCHRONIZATION AND ELECTRONIC PROJECTS FOR FPGA BASED PLATFORMS OF NPP SAFETY SYSTEMS

Abstract

Modern nuclear power plants require extremely high levels of reliability and functional safety from digital instrumentation and control systems, particularly those implemented on FPGA platforms. A critical challenge for such systems is the mitigation of common-cause failures, which may arise due to synchronous switching activity, electromagnetic disturbances, power supply transients, or design-level correlations between identical functional channels. Traditional diversity techniques based on hardware redundancy or component heterogeneity are often insufficient for programmable logic devices, where identical timing behavior and shared clock domains can lead to correlated faults.

This paper proposes methods and practical means of diverse synchronization for FPGA-based safety-critical systems. The approach is based on intentional phase shifting of functionally equivalent processing channels and clustering of logic blocks to achieve temporal decorrelation of switching activity. A multicluster clock-phase model is developed that enables controlled distribution of logic transitions across clock cycles, thereby reducing peak switching activity, lowering dynamic power consumption, and increasing tolerance to synchronous disturbances. The methodology includes analysis of switching diagrams, identification of peak load intervals, determination of optimal phase offsets under real-time constraints, and iterative simulation of clustered execution schedules.

Quantitative evaluation using switching activity metrics demonstrates a significant reduction of peak simultaneous transitions and an overall decrease in logic activity, confirming the effectiveness of the proposed technique. The study also introduces additional FPGA-oriented diversity mechanisms, including structural placement diversity, timing-path diversity through synthesis constraints, and functional diversity of checksum computation modules. These measures collectively provide a transition from passive redundancy to an active diversity strategy aimed at minimizing correlated risks.

The proposed solutions have been implemented in certified FPGA modules intended for nuclear power plant safety systems and validated against relevant international standards. The results confirm the scalability, practical applicability, and regulatory relevance of the developed methods for safety-critical digital architectures. The approach can be extended to other high-integrity domains such as energy, transportation, aviation, and industrial automation, where predictable behavior and resistance to common-cause failures are essential.